Is content by paid or sponsored bloggers seen as any more or less trustworthy than that provided via "earned" media? Apparently so. But this won't stop the growth of social media sponsorship.

Fleishman-Hillard's 2010 Digital Influence Index shows blogs remain an important channel via which consumers find news and reviews. However, consumer trust lowers significantly when readers discover a blogger has been paid or received a free sample.

Overall, 76% of those surveyed said they were less inclined to trust content written by a blogger who had received a free sample and less than 20% trust blog posts written by writers paid by a company.

Despite this mistrust, and even in light of the FTC's recent guidelines concerning disclosure, a report carried out earlier this year by PQ Media predicts the compensation of bloggers and social media influencers will grow 26% this year.

Over three-quarters (78%) of social media sponsorship campaigns are likely to be non-cash based instead offering virtual currency, virtual gifts or free product samples.

"Brand marketers move dollars to where their target consumers are spending time to build relationships with them and, as social media captures more of consumers' time, brands are warming to social media sponsorships as a new method to engage, educate and activate them," said Patrick Quinn, CEO of PQ Media.

"We believe this sector will be among the fastest-growing alternative media in the near future because of the growth of social media, driven by popular mobile and online applications and devices."